Edmund adoock



(No Model.)

E. ADCOCK.

PIRE EXTENSION LADDER.

No. 319,047. Patented June 2, 1885.

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EDMUND ADCOOK, OF CHICAGO, ILLINOIS, ASSIGNOR TO E. B. PRESTON ANDGEORGE E. PRESTON, OF SAME PLACE.

FIRE EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 319,049?, dated June 2,1885.

Application iiled April 25, 1885. (No model.)

To all whom it may concern:

Be it known that I, EDMUND Anacon, a citizen of the United States,residing at Ghicago, in the county of Cool; and State of Illinois, haveinvented a new and useful Improvenient in Fire Extension-Ladders, ofwhich the following is a specification.

This invention relates to extension-ladders, and more particularly tothe mechanism for raising and lowering the same. These ladders as usedby dre-departments are often of great length and are frequently requiredto sustain the weight of one or more men while in inclined positions, sothat great strain is thrown upon the mechanism which elevates the ladderand holds it in its elevated or inclined position.

The object of the present invention is to provide a simple, strong, andperfectly-rigid mechanism or means for elevating, lowering, and holdingthe ladder in any inclined posi tion; and to this end it consists, inconnection with a screw and its traveling nut, of a slideway-like that,for example, of a lathebolted or secured rmly to the turn-table, and inwhich said traveling nut moves back and forth. The lower end of the mainladder or its brace is connected to this traveling nut by a pivotedlink. By this means the slideway, which may be made perfectly stiff andrigid, receives and sustains all transverse strains, and prevents anyvibration of the screw.

In the accompanying drawings, which form part of' this specification,and in which similar letters of reference indicate like parts, Figure 1is a side elevation of a device embodying my invention. Fig. 2 is a planor top view. Figs. 3 and 5 are end or front and rear views of theslideway and traveling nut. Fig. 4 is a cross-section through theslideway and traveling nut, and Fig. 6 is a section through the box orbearing at the end of the screw.

In said drawings, A represents the truck; B, the bed-plate 01;stationary ring of the turn-table, secured to the frame of the truck;and B is the revolving ring or plate of the turn-table upon which theladder is mounted.

C is the main ladder, and c the shaft or pivot upon which it turnsand'is supported.

This shaft c is journaled and supported at each end in suitable bearingson the standards G', which are secured by suitable bolts to therevolving ring B.

The lower end of the ladder is strengthened by brace-arms C2 C3. l

D is the slideway plate or bar, rigidly se cured by suitable bolts orotherwise to the revolving ring B of the turn-table.

The groove or way in which the traveling nut or block E slides back andforth is preferably made by forming a groove, d, in the'.`

plate D, by rolling or otherwise, and then bolt-ing the overlappingplates d on each side. The slide or nut E of course conforms incross-section to the slideway in which it travels.

F is the screw by which the slide E is moved back and forth to raise andlower the ladder. It is journaled at each end in suitable boxes orbearings, F", bolted securely to the slideway plate D, and it isprovided with collars or shoulders f to hold it in place longitudinally.

The sliding nut or block E is provided with suitable trunnions orpivot-bolts, e, by which it is pivotally connected with the linlrs G,

which are pivoted at their other ends to the brace-arms (l2 G3 at theirangle by a bolt, g.

H is the crank or lever by which the screw is turned.

By this means not only is the mechanism madevery strong and rigid andall transverse strains prevented from coming upon the screw, but themechanism is adapted to operate at the best advantage for the easy andexpeditious raising and lowering of the ladder; and when the ladder iselevated to any position, it is there firmly and rigidly held, as thescrew and nut are prevented from. vibration or movement by the slideway.

In the drawings simply the lower end of the main ladder .is shown, asthe invention is equally applicable to any of the customary forms orconstructions of extensiondadders.

The brace-arms C C 3 not only serve to strengthen the lower end of theladder about its support or pivot, but also to throw the line of draftmore nearly on a line with the direction of the screw.

IOO

I claim- C, of brace-arms C2 C3, turn-table ring'B,

l. The combination, with a hinged or pivslideway D, sliding nut or blockE, screw F, Io oted ladder, of a turn table, a slidcway scand pivotedlink G, substantially as specified. cured to said turn-table, a slidingblock or T 5 nut traveling in said way, 2n screw, and a pv- EDMULDADGOCK oted link connecting,` said sliding block and Vibnesses: ladder,substantially as spccied. J oHN YV. MUNDAY,

2. The combination, with pivoted ladder CHAS. J. BAUR.

